The connection speed issue only started happening after updating from High Sierra to Catalina. Prior to the update, Brave usually tested on speedtest at the higher proper speeds (over 200Mb).
Here’s where someone else had the same speed issue:
https://community.brave.app/t/slow-internet-speeds-compared-to-safari-fiber-gig-internet/
I’m waiting for the fan to kick in to look at the Task manager.